Which of the following is a linear function? a. ƒ(x) = 2 – 7x b. ƒ(x) = 2 + x + x2 c. ƒ(x) = √ 2 + 7x

A linear function has 1 as the highest power of the variable.

A. f(x) = 2 - 7x

here, the highest power of the variable x is 1.
Hence it is a LINEAR function.
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B. f(x) = 2 + x + x^2

here, the highest power of the variable x is 2.
Hence it is NOT a linear function.
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here, the highest power of the variable x is 1/2.
Hence it is NOT a linear function.
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